Acute electrocardiographic lead II changes following experimental pulmonary air embolization

ABSTRACT

The effect of venous air embolization on the heart's electrical activity is not well demonstrated in the literature. This is a study of the acute electrocardiographic [ECG] lead II changes following experimental injection of 40 ml of air in two groups of dogs [7 dogs in each group]. In group I [GI], air was injected peripherally in the femoral vein and in group II [GII], air was injected directly into the central pulmonary artery. Six dogs were used as control. All dogs were subjected to general endotracheal anesthesia and sternotomy to expose the heart. ECG changes were recorded using lead II. Cardiac dysrhythmia was the most frequently encountered ECG change. It occurred in 85.7% of dogs of GI and in 100% of dogs of GII. Sinus tachycardia was the commonest in GI [85.7%]. Sinus tachycardia and premature ventricular contractions were commonest in GII [42.8% each]. The incidence of T wave inversion was greater in GI [42.8%], while ST segment changes were greater in GII. The only significant difference between the two groups was the presence of P-pulmonale in GI only [57.1%]. Venous air embolism should be thought of in patients with any access to their systemic venous circulation and whose monitoring reveals unexplained ECG changes